Control device for internal combustion engine

Patent metadata

Field	Value
Publication number	US-9567938-B2
Application number	US-201114350891-A
Country	US
Kind code	B2
Filing date	Oct 11, 2011
Priority date	Oct 11, 2011
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

Abstract

A control device for an internal combustion engine includes first and second intake ports ( 16 a, 16 b ) independent of each other, and first and second fuel injection valves ( 30 a, 30 b ) provided for the first and second intake ports ( 16 a, 16 b ), respectively, in each cylinder. Under a situation where an exhaust variable valve mechanism ( 38 ) is controlled such that a first exhaust valve ( 32 a ) is opened earlier than a second exhaust valve ( 32 b ), first and second air-fuel ratios A/F1, A/F2 are respectively obtained in a first half and a second half of an exhaust stroke. When the obtained first air-fuel ratio A/F1 (or the second air-fuel ratio A/F2) is lean, a fuel injection amount in a next cycle by the first or second fuel injection valve ( 30 a, 30 b ) corresponding to the first air-fuel ratio A/F1 (or the second air-fuel ratio A/F2) that is lean is reduced.

First claim

The invention claimed is:

1. A control device for the internal combustion engine including plural intake ports that are provided in a same cylinder and are independent of each other, plural intake valves that respectively open and close the plural intake ports, plural fuel injection valves that are respectively provided for the plural intake ports and can respectively inject fuel toward the plural intake ports, plural exhaust valves that are respectively disposed near the plural intake valves, plural exhaust ports that are respectively opened and closed by the plural exhaust valves, and
an exhaust air-fuel ratio obtaining unit that separately obtains air-fuel ratios of exhaust gas discharged from the plural exhaust ports during an exhaust stroke, the control device comprising:
a controller configured to control a fuel injection amount to be injected in a next cycle toward the intake port near the exhaust port that correspond to the air-fuel ratio of the exhaust gas separately obtained by the exhaust air-fuel ratio obtaining unit such that each of the air-fuel ratios of the exhaust gas from the plural exhaust ports corresponds to a specified target air-fuel ratio on the basis of each of the air-fuel ratios of the exhaust gas from the plural exhaust ports separately obtained by the exhaust air-fuel ratio obtaining unit, wherein
the plural intake ports are first and second intake ports,
the plural intake valves are first and second intake valves that respectively open and close the first and second intake ports
the plural fuel injection valves are first and second fuel injection valves that are respectively provided for the first and second intake ports,
the plural exhaust valves are a first exhaust valve that is disposed near the first intake valve and a second exhaust valve that is disposed near the second intake valve,
the plural exhaust ports are first and second exhaust ports that are respectively opened and closed by the first and second exhaust valves,
the exhaust air-fuel ratio obtaining unit separately obtains first and second air-fuel ratios of the exhaust gas discharged from the first and second exhaust ports during the exhaust stroke,
the controller reduces the fuel injection amount in the next cycle by at least one of the first and second fuel injection valves that corresponds to at least one of the first and second air-fuel ratios that is lean when at least one of the obtained first and second air-fuel ratios is leaner than the target air-fuel ratio,
wherein the internal combustion engine includes an exhaust valve mechanism that is set such that opening timing of the second exhaust valve is delayed from opening timing of the first exhaust valve in the same cylinder or that can relatively change the opening timing of the first and second exhaust valves during an operation of the internal combustion engine such that the opening timing of the second exhaust valve is delayed from the opening timing of the first exhaust valve in the same cylinder,
the exhaust air-fuel ratio obtaining unit includes an air-fuel ratio sensor that detects an air-fuel ratio of the exhaust gas that flows through a merged exhaust passage after the exhaust gas from the first exhaust port and the exhaust gas from the second exhaust port merge together, and
the exhaust air-fuel ratio obtaining unit obtains the air-fuel ratio of the exhaust gas that is detected by the air-fuel ratio sensor at timing when the exhaust gas discharged from the first exhaust port reaches the air-fuel sensor in a period when only the first exhaust valve is opened as the first air-fuel ratio, and obtains the air-fuel ratio of the exhaust gas that is detected by the air-fuel ratio sensor at timing when the exhaust gas discharged from the second exhaust port reaches the air-fuel ratio sensor in a period when the second exhaust valve is opened in an exhaust stroke thereafter as the second air-fuel ratio.

2. The control device for the internal combustion engine according to claim 1 , wherein
a length of a second exhaust passage from the second exhaust valve to an arrangement portion of the air-fuel ratio including the second exhaust port is longer than a length of a first exhaust passage from the first exhaust valve to the arrangement portion of the air-fuel ratio sensor including the first exhaust port.

3. The control device for the internal combustion engine according to claim 1 , wherein
the internal combustion engine further includes a NOx catalyst of occlusion/reduction type,
the controller executes rich spike control in the next cycle by using at least one of the first and second fuel injection valves when an integrated value of deviation in the air-fuel ratio between the first air-fuel ratio and the second air-fuel ratio that is obtained by the exhaust air-fuel ratio obtaining unit for each cycle reaches a specified determination value.

4. The control device for the internal combustion engine according to claim 1 , wherein
the controller controls the exhaust variable valve mechanism such that only one of the first exhaust valve and the second exhaust valve is opened when the internal combustion engine is cold.

5. A control device for the internal combustion engine including plural intake ports that are provided in a same cylinder and are independent of each other, plural intake valves that respectively open and close the plural intake ports, plural fuel injection valves that are respectively provided for the plural intake ports and can respectively inject fuel toward the plural intake ports, plural exhaust valves that are respectively disposed near the plural intake valves, plural exhaust ports that are respectively opened and closed by the plural exhaust valves, and
an exhaust air-fuel ratio obtaining unit that separately obtains air-fuel ratios of exhaust as discharged from the plural exhaust ports during an exhaust stroke, the control device comprising:
a controller configured to control a fuel injection amount to be injected in a next cycle toward the intake port near the exhaust port that correspond to the air-fuel ratio of the exhaust gas separately obtained by the exhaust air-fuel ratio obtaining unit such that each of the air-fuel ratios of the exhaust gas from the plural exhaust ports corresponds to a specific target air-fuel ratio on the basis of each of the air-fuel ratios of the exhaust gas from the plural exhaust ports separately obtained by the exhaust air-fuel ratio obtaining unit, wherein
the plural intake ports are first and second intake ports,
the plural intake valves are first and second intake valves that respectively open and close the first and second intake ports
the plural fuel infection valves are first and second fuel injection valves that are respectively provided for the first and second intake ports,
the plural exhaust valves are a first exhaust valve that is disposed near the first intake valve and a second exhaust valve that is disposed near the second intake valve,
the plural exhaust ports are first and second exhaust ports that are respectively opened and closed by the first and second exhaust valves,
the exhaust air-fuel ratio obtaining unit separately obtains first and second air-fuel ratios of the exhaust gas discharged from the first and second exhaust ports during the exhaust stroke,
the controller reduces the fuel injection amount in the next cycle by at least one of the first and second fuel injection valves that corresponds to at least one of the first and second air-fuel ratios that is lean when at least one of the obtained first and second air-fuel ratios is leaner than the target air-fuel ratio, wherein
the internal combustion engine further includes:
an exhaust valve mechanism that is set such that the first exhaust valve is opened before
the second exhaust valve is opened and then the second

Assignees

• Mori Sachio
• Toyota Motor Co Ltd

Inventors

• Mori Sachio

Classifications

• F02D41/0002

  Controlling intake air · CPC title

• F02D13/0257

  Independent control of two or more intake or exhaust valves respectively, i.e. one of two intake valves remains closed or is opened partially while the other is fully opened · CPC title

• F02D13/0249

  changing the valve timing only · CPC title

• F02D41/1455

  with sensor resistivity varying with oxygen concentration (F02D41/1456 takes precedence) · CPC title

• F02M35/10177

  Engines having multiple fuel injectors or carburettors per cylinder · CPC title